Recurrent Selection by Herbicide Sublethal Dose and Drought Stress Results in Rapid Reduction of Herbicide Sensitivity in Junglerice

Abstract

Echinochloa colona (junglerice) is a problematic global weed for many crops, primarily controlled with herbicides. Drought stress alters the overall plant physiology and reduces herbicide efficacy. This research aimed to study the joint effect of drought stress (DS) and recurrent selection with sublethal dose of herbicide on adaptive gene expression and herbicide efficacy on E. colona. Three factors were evaluated: (A) E. colona generation (G0, original population from susceptible standard; G1 and G2, progenies of recurrent selection); (B) herbicide treatment (florpyrauxifen-benzyl, 0.25×; glyphosate, 0.125×; quinclorac, 0.125× the recommended dose; and nontreated check); (C) DS (50% and 100% field capacity). Recurrent exposure to sublethal herbicide dose, combined with drought stress, favors the selection of plants less susceptible to the herbicide. Upregulation of defense (antioxidant) genes (APX: ascorbate peroxidase), herbicide detoxification genes (CYP450 family: cytochrome P450), stress acclimation genes (HSP: heat-shock protein, TPP: trehalose phosphate phosphatase, and TPS: trehalose phosphate synthase), and genes related to herbicide conjugation (UGT: UDP glucosyltransferase) in the G2 population was significant. Recurrent exposure to sublethal herbicide dose under drought stress reduces junglerice sensitivity to herbicide, seemingly due to “imprinted” upregulation of metabolic and protection genes in response to these stresses.

Recurrent Selection with Low Herbicide Rates and Salt Stress Decrease Sensitivity of Echinochloa colona to Imidazolinone

“…Markus et al [36] and Rouse [37] proposed epigenetic regulation models that may be involved in herbicide resistance and adaptation to abiotic stresses. Additionally, Benedetti et al [15,21] reported a reduction in sensitivity to certain herbicides in E. colona submitted to the recurrent selection of sublethal doses of herbicides and abiotic stresses, as drought and heat.…”

“…We hypothesize that non-target site weed resistance evolution may be driven by sublethal rates of herbicides and by environmental stresses such as heat stress, drought stress, and salt stress [15,21]. Climate change impacts on the ecosystem need attention, such as soil and saline water management and the dynamics of interactions [22].…”

Rapid Reduction of Herbicide Susceptibility in Junglerice by Recurrent Selection with Sublethal Dose of Herbicides and Heat Stress

“…The study of adaptation mechanisms to environmental and herbicide stress in Echinochloa colona is important since plants are constantly exposed to such stresses. Concurrent exposure to environmental stress can facilitate the evolution of tolerance to new herbicides and different MOAs, as demonstrated by Benedetti et al [104] where observed that recurrent selection by a herbicide sublethal dose and drought stress results in rapid reduction of herbicide sensitivity in junglerice. This research provides information on the reduction of sensitivity to herbicides under high temperature and, thus, the imminent acceleration of weed resistance evolution to herbicides under heat stress (Figure 4).…”

Ten Ways That Weed Evolution Defies Human Management Efforts Amidst a Changing Climate

“…Increasing temperatures can reduce herbicide efficacy because of more rapid plant metabolism at higher temperatures and/or increased evaporation from the soil, although these effects vary by site and for particular weed species [106][107][108]. When Benedetti et al [109] exposed Echinochloa colona (L.) Link (junglerice) to repeated low doses of herbicides under two heat stress levels (30 and 45 • C), they found that several genes were upregulated in junglerice that tended to increase herbicide tolerance.…”